What are industrial minerals & functional fillers?
A brief explanation
Industrial minerals and functional fillers are broken down and carefully prepared, mostly from natural rocks typically found above ground and more rarely underground. This usually includes pre-sorting processes in which a targeted enrichment of the desired minerals and a reduction of the accessory minerals take place. The subsequent grinding steps guarantee uniform particle size distributions, which are absolutely essential to many applications.
In this way, natural stones yield high-performance fillers which, thanks to their particle shape, size and structure, guarantee uniquely improved characteristics in applications involving paints, varnishes, adhesives and construction applications, and often on very attractive terms. This is why we like to call them “functional fillers.”
Further processing steps
However, there is still a very long way to go before exhausting all the possibilities. With certain products, thermal processing steps or chemical deposition processes follow, which lead to modifications of the mineral structure or to an additional cleaning, and then ultimately to changed functionalities.
Certain natural as well as some modified mineral products can then be selectively surface treated in order to achieve improved bonding in the various binding systems.
Products
The following products are particularly suitable for use in paints and varnishes, adhesives and in construction applications:
Natural fillers
Mineral group | Designation | Properties | Functionalities/applications |
---|---|---|---|
Silicates | Kaolin | Lamellar, natural and calcinated types; delaminated, ultrafine to coarse, plastic, soft Mohs hardness 2-2.5, some types with quartz content of approx. 0.1 % by weight | TiO2-extender, calcinated as matting agent, improvement of edge use, crack bridging, for satin to matte finishes, especially for aqueous formulations, increased coverage, good flow properties; best for decorative paints, but also for dispersion adhesives |
Silicates | Talc | Lamellar, very white, fine to coarse types, color-neutral, plastic, very soft Mohs hardness 1 | Matting agent, improvement of edge use, crack bridging, particularly suitable for formulations containing non-polar solvents, supports hydrophobic properties; improves wet abrasion resistance, for both industrial varnishes and dispersion paints |
Silicates | Mica | Lamellar, very high aspect ratio, elastic, relatively soft Mohs hardness 2.5-3 | Low oil absorption, crack bridging, reinforcement, barrier effect, improvement of wet abrasion resistance, suitable for glimmer effects, for dispersion paints and plasters, for corrosion-protection paints |
Silicates | Wollastonite | Acicular, aspect ratio up to 1:9 | Strengthening, reinforcement, crack bridging |
Silicates | Diatomaceous earth | Naturally and flux-calcinated, large spec. surfaces | Strong matting agent (flux-calcinated), increased abrasion resistance, for decorative paints |
Silicates | Nepheline syenite | Corpuscular, chemically inert | Low refractive index, therefore practically invisible in many resin systems, increased scratch resistance, for industrial varnishes |
Silicon dioxide | Quartz | Corpuscular, chemically inert, hard Mohs hardness 7 | Sharp increase in abrasion resistance, weather resistant, surface-treated in corrosion protection applications |
Silicon dioxide | Cristobalite | Corpuscular, chemically inert, hard (Mohs hardness 6.5), very white, color-neutral | Stable in exterior and industrial varnish applications, minimal need for binders, surface treated in corrosion protection applications |
Carbonates | Calcite | Chalk, limestone, marble, corpuscular, cream colored to pure white, Mohs hardness 3 | Optimization of packing density, very cost-effective, minimal need for binders, buffering properties in basic systems, for dispersion paints, dispersion adhesives and many more |
Carbonates | Dolomite | White, color-neutral | Optimization of packing density, cost-effective, minimal need for binders, for decorative colors |
Oxides | Micaceous iron oxide | Lamellar, chemically inert, high density, gray metallic shine, Mohs hardness 6-6.5 | Passive corrosion protection pigment, micronized as Zn-dust substitute, effect pigment |
Sulfates | Barium sulfate | Corpuscular, chemically inert, high density, white | Minimal need for binder, high fill content possible, good coverage, especially for industrial varnishes |
Sulfates | Gypsum | Corpuscular, chemically inert, Mohs hardness 2 | Low in heavy metals, filler for construction materials and adhesives |
Sulfates | Anhydrite | Corpuscular, chemically inert, white | Filler for adhesives |
Mineral mixtures | Clay | Mostly lamellar, basic color white to earth tones, chemically inert | Partially very plastic, cost-effective filler, also for wood varnishes |
Mineral mixtures | Slate | Lamellar, basic color beige-gray to gray | UV protection in bitumen, sound absorbing, very cost-effective |
Mineral mixtures | Greenschist | Lamellar to corpuscular, basic color green | Cost-effective, sound absorbing |
Synthetic Fillers
Mineral group | Designation/properties | Properties | Functionalities/applications |
---|---|---|---|
Silicates | Glass beads | Ideally round, very smooth surfaces, amorphous, color-neutral | enable very smooth surfaces, increased scratch resistance, very minimal influence on viscosity, amorphous; surface-modified types display better incorporation in binder systems, minimally abrasive due to grain shape, minimal dulling, particularly suited to wood varnishes |
Silicates | Hollow glass beads | Ideally round, very smooth surfaces, amorphous, color-neutral | Significant weight reduction, improved insulation properties, in various pressure stabilities, for lightweight construction systems |
Silicates | Lightweight fillers | Corpuscular or round, hollow interior, light gray or cream colored | Significant weight reduction, improved insulation properties, in various pressure stabilities, for heat and sound dampening, among others |
Carbonates | Precipitated calcium carbonate | Corpuscular, very white, color-neutral, grain size controllable | High coverage, tight grain distribution curves, TiO2 extender, very white, also available in pharmaceutical grade, for dispersion paints |
Sulfates | Precipitated barium sulfate | Corpuscular, very white, color-neutral, chemically inert | High coverage, tight grain distribution curves, chemically inert, TiO2 extender, minimal need for binders, for industrial varnishes |
Oxides/hydroxides | Aluminum oxide | Very white, very hard (Mohs hardness 9) | Improved abrasion resistance, for flooring systems |
Oxides/hydroxides | Aluminum hydroxide | Very white, chemically inert, color-neutral | Flame retardant |
Service & Support
Contact
BASSERMANN minerals
Dipl.-Ing. Adrian Zanki
Department Manager Industrial Minerals & Functional Fillers